Containers have long been used in a wide variety of industries to collect, store, and dispense various substances. Most traditional containers have an opening into an internal cavity and are provided with a cap for sealing the cavity. The seal is often achieved by the interaction of threads, a snap-fit, or by using a separate strap to attach the cap. Because caps are typically produced separately from containers and are especially susceptible to being lost or misplaced, some manufactures have found it desirable to produce containers having integrally-formed caps.
This is especially true in fields where the cap is used to seal the container so that the internal cavity remains sterile prior to use. For example, U.S. Pat. No. 4,783,056 to Abrams, the disclosure of which is incorporated herein by reference in its entirety, discloses a process for forming a vial having an integral cap. The process generally comprises positioning a first mold part relative to a second mold part to define a cavity having the shape of the vial, the cap and a connecting strap or flange extending between the vial and cap. After injecting molten thermoplastic material into the cavity and letting it cool, the first mold part is moved away from the second mold part. A pivot member, such as a “flipper arm”, may then be pivoted to seal the cap onto the vial prior to releasing the final product from the mold. Thus, by closing the cap while the vial is still within the mold, the heat of the molding process is used to maintain sterility. Additional steps to seal the cap in an aseptic environment are not required, which reduces overall manufacturing costs and production times.
One of the drawbacks associated with this process, however, relates to its inability to produce containers of various shapes and sizes. Because the injection molding process requires separate mold pieces that must be moved apart from each other to release the final product, the shape of the resulting containers is oftentimes limited to that of a vial. In other words, the containers are often generally cylindrical in cross-section with little or no variation in diameter along their length.
Although some attempts have been made to blow mold a preform or parison after it has been injection molded to ultimately form a bottle or similar container having an integral cap and a receptacle with varying width, there are currently several drawbacks that limit the effectiveness of such attempts. For example, U.S. Pat. No. 5,008,066 to Mueller, discloses a method of forming a container having an integral cap involving both an injection molding step and a blow molding step. The injection molding step produces an open-ended, generally cylindrical preform, which is subsequently blow molded to expand the preform into a cavity that defines the final shape of the container. In the process of Mueller, two separate injection and blow molding stations are required. The molded preform is ejected from the injection molding station and then it must be transferred to the blow molding apparatus station where it is blow molded into the final container shape. The result is an increase in required machinery, production times, and overall costs.
Therefore, there is a need for an improved apparatus and method for forming a container having a receptacle and integral cap.